Circulatory lubricating system for rotary blowers



Sept. 11, 1934. o. BECKER. JR

CIRCULATORY LUBRICATING SYSTEM FOR RQTARY BLOWER S Filed Jan. 21. 1931 2 Sheets-Sheet 1 Patented Sept. 11, 1934 UNITED STATES CIRCULATORY LUBRICATING SYSTEM FOR ROTARY BLOWERS Otto Becker, Jr., wuppertal Barmen, Germany Application January 21, 1931, Serial No. 510,306

In Germany April 10, 1930 v 2 Claims.

Application has been filed in Germany April 10, 1930. a

The present invention relates to a circulatory lubricating system for rotary blowers, vacuum 5 pumps or motors having an oil supply chamber arranged in the base of the casing of the blower and in connection with the pressure chamber of the blower.

Hitherto the lubrication of machines of this class has been effected by means of drip lubricators or with the aid of the excessor underpressure produced by the blower in which case the lubricant is conducted to the cylinder of the rotary piston on the suction side. The disadvantage exists in this case that, owing to the variations in temperature and pressure which occur, the quantity of oil which is supplied varies and frequent re-adjustment becomes necessary which is especially diflicult and troublesome with so the very small amounts of oil which are necessary. Furthermore this kind of lubrication also has the disadvantage that the oil supplied to the suction side of the blower is already atomized into a fine mist, before it is distributed on the surface to be lubricated, owing to the gas eddying in the working cylinder of the blower, which has an unfavourable effect on the lubrication since only a small indeterminate part of the quantity of oil supplied is used for lubrication.

This drawback is particularly prominent in the case of vacuum pumps as the vacuum is extremely favourable to the atomization or vapourization of the lubricant. Further removal of the lubricant mist from the stream of gas delivered is extremely diificult.

These drawbacks are substantially avoided in accordance with the present invention by supplying the lubricant taken from the lubricant supply container which is in connection with the co pressure chamber of the blower by means of a separate pump, which is coupled to the blower, to the pressure side of the cylinder of the rotary piston, namely behind the outlet slit or immediately in front of the inner dead point of the blades of the blower which are displaceably arranged in the rotary piston. The result is thereby obtained that the oil supplied is pressed into the blade grooves and is well distributed over the surfaces to be lubricated so that, when the to blade passes over into the suction chamber of the blower the oil adheres to the blades or the wall of the cylinder and can no longer be atomized.

Preferably in this case, in accordance with the uivention, the arrangement of the rotary piston is such that the outlet slits of the cylinder of the blower are directed downwardly towards the oil bath located in the base of the pressure chamber of the blower, and therearepreferablyarranged between the outlet slits andth'e' oil bath bafile plates which prevent the stream of gasemerging from the cylinder from directly striking the oil bath and thereby stirring up the latter, they have also a flavourable effect in separating the oil emerging with the gas. Owing to this special arrangement of the outlet slits, the latter can be distributed overthe entire length" of the cylinder of the blower whereby the speed at which the gas emerges is reduced to'such extent that pressure losses of the latter as well as atomization of the oil carried by them is avoided. v

The construction and arrangement of the lubrieating pump which is provided in accordance with the invention, can advantageously be such that the pump is directly built on to the'blower' casing and is driven by way of two worm gears from the shaft of the rotary piston of the blower. In this case the pump piston-which rotates about its own axis and is moved backwards and forwards by a grooved disc can directly control the inlet and outlet of the lubricantin the pump-cylinder by being provided at its operative end with a longitudinal bore which is connected by radial bores in the piston, according to the position of the latter in its stroke, alternately with passages arranged in the cylinder casing and connected to the suction and pressure pipes. In order in this case to be able to connect the pump with several pressure pipes for the lubricant leading to the lubricating places of the blower and of the'pump and thus to obtain the most suitable pressure for the individual pressure pipes the grooved. disc for controlling the pressure stroke of the piston of the pump is in accordance with the invention divided into several stages, by suitably stepping the curve of the groove in the disc, whereby at the end of each individual pressure stroke one of the pressure pipes for the lubricant is connected with the interior of the piston or with the pressure Fig. 5 shows a development of the grooved disc for moving the piston of the pump backwards and forwards.

Referring to the drawings, the casing 1 or the blower carries in its interior the cylinder 2 in which the rotary piston is arranged eccentrically in known manner. The rotary piston 3 is fixed on the shaft 4 and is provided with radial slots 5 in which the blades or shutters 6 slide backwards and forward. The rotary piston 3 is arranged eccentrically in known manner so that between the piston 3 and the cylinder 2 there is formed a crescent shaped space 7, 8 which is connected with suction and pressure chambers 11 and 12 respectively in the casing l by means of slits or ports the ends of which are indicated in the drawings by the lines 9 and 10 respectively and are arranged in the cylinder jacket 2 above and below theline joining the inner and outer dead points x, y of the blades 6. Of these two chambers 11, 12 the latter 12 is made considerably larger and is provided with a sunk base 13 which serves the purpose of a supply container for the oil A necessary ifor lubricating the blower. The amount of oil A present in the container can be observed by means of two sight glasses 14, 15 provided atpeither side of the casing 1 of the blower. The container in the base 13 can be filled with or emptied or the oil A by means of holes 18 and 19 which are closed by means of screws 16, 17.

According to the present invention the two dead points at, y of the blades 6 of the rotary piston are so arranged that the outlet slits 10 which lead into the pressure chamber 12 in the casing are directed downwardly towards the oil bath A while between the outlet slits 10 and the oil bath there is arranged a baffle-plate 20 which is fixed to the cylinder 2 and prevents the oil bath A from being agitated or stirred up by the outfiowing current of gas. To a lateral outlet 21 of the pressure chamber 12 there is connected a regulating valve 22 which can be adjusted by weights 23 or springs to the highest pressure desired in the pressure chamber 12, so that if this pressure is exceeded the valve 21, 22 opens automatically and etlects a reduction in pressure.

The lubrication of the blower is effected, in

accordance with the invention, by a piston pump which is coupled to the blower and sucks up the oil through a suction pipe 24 leading into the oil-supply container 13 and then conducts it under pressure through several pipes 25, 26 to the parts B, C of the blower which have to be lubricated. In the example illustrated the blower is provided with two lubricating places B, C which are arranged, in accordance with the invention, between the outlet slits 10 and the inner dead point :1: of the blades 6 or the point of contact a:

of the rotary piston 3 with the cylinder 2. The

lubricating pump is provided, as may be seen from Figs. 3 and 4 of the drawings, with a piston 27 which rotates about its own axis and is 'directly driven through the agency of two worm gears 28,29 and 30, 31 respectively from the ..haft 4 of the rotary piston of the blower: By this means a great reduction in the speed of revolution of the piston of the lubricating pump is obtained while the external dimensions of the lubricating pump are kept extremely small, so that in combination with the direct attachrn'ent ot the pump to the casing of the blower an extremely simple and pleasing-shape of the entire machine is obtained. The worm wheel 31 of the gear 30, 31 is arranged on the piston 27. of the pump in such a manner that it is fixed therewith but displaceable thereon. Further there is fixed on the piston a grooved disc 32, in the groove 33 of which a pin 35 fixed in the pump casing 34 engages. By suitably shaping-the. groove 33, the

development of which is illustrated mFig. 5, a backward and forward movement-producing the suction and pressure stroke of the pump is imparted to the pump piston 2'7 during its rotation. The inlet and outlet of the lubricant to or from the pump chamber 36 is controlled by the pump piston 27 itself, in that the latter is provided at its operative end with a longitudinal bore 37 which opens into the pump chamber 36 and is connected by radial bores 38, 39, 40, 41 of the piston, according to the position of the latter in its stroke, with passages 42, 43, 44, 45 in the pump casing 34 which are connectedto the suction pipe 24 and the pressure pipes 25, 26 of the pump. In the example illustrated three pressure passages 43, 44, 45 and one suction passage 42 are provided, these are relatively displaced by and are arranged so that they are distributed along the length of the piston 27. The pressure stroke of the pump piston is consequently divided into three stages by a multiple stepping of the controlling groove 33 of the grooved disc 32. As the step or inclined portion a of the groove 33 moves past the pin 35, the pump performs its suction stroke during which the opening 38 of the piston is brought into registry with the inlet or suction channel or port 42 and thus is connected; to thesuction tube 24. As the piston rotates to move, the small steps or inclined portions of the cam groove 33 past the pin 35, successive pressure movements of the piston are produced and the piston opening or port 39 is brought in registration with the outlet openings or ports 45, 44 and 43 successively. Thus the piston bore 37 and cylinder chamber communicate with the ports 45, 44 and 43 in-succession? "0i these pressure passages the two'passages, 43' a'ndf 45 deliver part .of the lubricant which. uked up by the pump tolthe'two lubricatingl placesB, C or the blower, while the'pressure passage;;44dlivers the remaining oil by way or j 'separatej passages to the lubricating placesof, the pump.,, The end of the pump cylinder BGbeyQnd thepi'ston 27 is limited by a headscrewi46 which is screwed into the bore36 of the cylinderffThe driving parts of the pump are closed. tightly tothe outside by a removable cover 47 while the whole pump is then additionally covered by a hood-like, casing 48. V

The method of operation of the complete machine is as follows:- I

If the rotary piston 3 of the blower is rotated in the direction of the arrow 2, the blades 6 suck 'up air or gas through the inlet slits 9 which are in connection with the suction chamber 11 0f the flower until the next following blade cutsoff the inlet 'slits 9. The volume of gas between the latter and the preceding blade is then compressed owing to the gradual narrowing of the cylinder space 8 and emerges through the outlet silts 10 into the pressure chamber 12 of the blower before reaching the inner dead point a: of the blade. The emerging stream of gas then impinges on the baflle-plate 20 on which any particles of oil emerging with it are deposited and flow back into the oil bath A. If more gas is delivered than is removed from the pressure chamber 12 or if the pressure in the chamber 12 becomes excessively high, the valve 22 opens and the pressure is reduced. During the rotation of the piston 3,

first, as is shown in Figure 4, the step a of the groove 33 passes the fixed pin 35. This causes the piston 27 to retract and to suck oil out of the oil sump 13 through the pipe 24, port 42 and piston port 38. Next, upon rotation of the piston then the step b passes the pin and the piston moves forwardly and at the same time the port 39 registers with the port 45 so that oil may iiow out and through the pipe 25 to the locality B to be lubricated. Again the piston rotates to move the step c past the pin and the piston performs a second forward movement, during which the port 39 registers with the port 44 so that oil is forced out through the port 44 to whatever place or places the port may be connected. Finally, a third rotation of the piston through 90 causes the step d to pass the pin and thereby effects a third forward movement of the piston, during which the port 39 registers with the port 43 and thus oil is forced through port 43 and pipe 26 to the location C of the blower. The full pressure stroke of the piston will now have been completed and the cycle will start again with the next rotation of 90 effecting the suction stroke of the piston. A continuous filling of the cylinder 36 of the pump during the suction stroke is ensured by the pressure on the oil bath A whereby in combination with the con-' stant pressure in the delivery pipes obtained by the special construction of the pump the same quantity of oil is always delivered to the lubricating places independently of temperature and pressure and good and uniform lubrication of the machine is thereby ensured.

The invention is of course not limited to the example illustrated but other forms of construction are possible particularly as regards the arrangement and construction of the lubricating pump. In particular, the machine instead of being employed as an operating machine could also be employed as a power machine.

I claim:-- v 1. A lubricating device for engines and pumps of the type having a cylindrical casing provided with spaced inlet and outlet ports and having an eccentrically disposed rotor provided with sliding vanes contacting the casing wall, said outlet port being located on the lower side of the casing, said lubricating device including a lubricant pump driven from saidroton-an outer casing below the cylindrical casing and forming a'lubricant supply tank from which the pump is supplied, a horizontal baille below the outlet port and above the surface of the oil to prevent disturbance of the oil by fluid flow from the outlet port, and means to deliver lubricant from-the pump to a. point slightly behind the outlet port and between said outlet port and the point of closest approach of the rotor to the casing wall.

2. A lubricating device for engines and pumps of ,the type having a cylindrical casing provided with spaced inlet and outlet ports and having an eccentrically disposed rotor provided with sliding vanes contacting the casing wall, said lubricating device including a lubricant pump driven from said rotor, the driving means for the pump con- 

